This invention relates to an ink cartridge for supplying ink to a record head, and an ink jet record apparatus using the ink cartridge.
An ink jet record apparatus generally comprises a record head mounted on a carriage and moving in the width direction of record paper, and paper feed means for moving the record paper relatively in a direction orthogonal to the move direction of the record head.
Such an ink jet record apparatus prints on record paper by ejecting ink droplets from a record head based on print data.
A record head capable of ejecting black ink, yellow ink, cyan ink, and magenta ink, for example, is mounted on a carriage, and in addition to text print in black ink, full-color print is made possible by changing the ink ejection percentage.
Thus, ink cartridges for supplying black ink, yellow ink, cyan ink, and magenta ink to the record head are placed in the main unit of the apparatus.
In the ordinary ink jet record apparatus, the ink cartridges for supplying black ink, yellow ink, cyan ink, and magenta ink are mounted on a carriage, and are moved together with the carriage.
On the other hand, in this kind of record apparatus provided for an office or business, for example, to deal with a comparatively large amount of print, the large-capacity ink cartridge storing each ink is not placed on the carriage and is placed in the apparatus main unit.
A record apparatus of the type wherein main tanks as ink cartridges are placed in the apparatus main unit (cartridge holder) and subtanks are placed on a carriage on which a record head is mounted is also provided. Ink is respectively supplied from the main tanks to the subtanks via ink supply tubes, and further from the subtanks to the record head.
In such a record apparatus, to improve throughput, such a function is required that can replenish ink from the main tanks to the subtanks in succession to stably supply ink from the subtanks to the record head, while print is executed.
By the way, nowadays, demand for high-accuracy print quality grows, and there is a tendency of using ink containing pigment (pigment ink), for example, as print ink.
Such pigment ink has a large particle diameter of color material as compared with ink containing a dye (dye ink), and pigment is likely to be collected and concentrated in the bottom portion of a cartridge (ink storage chamber), and therefore a concentration distribution (non-uniformity in concentration) easily occurs in the ink in the cartridge.
Thus, there arises a technical problem in that the ink in the cartridge is not sufficiently mixed at the use time and uniform print density and quality cannot be obtained.
It is therefore an object of the invention to provide an ink cartridge for making it possible to sufficiently mix ink in the cartridge at the use time and therefore provide uniform print density and quality. Another object of the present invention is to provide an ink jet record apparatus using the ink cartridge.
To the end, according to the invention, there is provided an ink cartridge being detachably connected to a head of a record apparatus and comprising a plurality of ink storage chambers for containing ink causing concentration gradient, and an ink flow passage for communicating the ink storage chambers with one another. In the cartridge, the ink flow passage has such an ink flow passage as to cause ink in a high-concentration ink layer formed in a lower area in the ink storage chamber and ink in a low-concentration ink layer formed in an upper area in the ink storage chamber to flow and merge with each other as ink is supplied to the record apparatus head.
Since the ink cartridge is thus configured, when ink is supplied to the record apparatus head, the ink in the high-concentration ink layer in the ink storage chamber and the ink in the low-concentration ink layer in the ink storage chamber flow and merge in the ink flow passage.
Therefore, the ink in the high-concentration ink layer and the ink in the low-concentration ink layer are mixed for supply to the record apparatus head, so that uniform print density and quality can be obtained.
Here, it is desirable that the ink storage chambers comprise a plurality of upper ink storage chambers including a head connection ink storage chamber that can be connected to the record apparatus head, and an atmosphere open lower ink storage chamber opened to the atmosphere in the connection state to the record apparatus head.
Since the ink cartridge is thus configured, ink is supplied to the record apparatus head by causing ink to flow from the lower ink storage chamber to the upper ink storage chamber.
It is desirable that the ink flow passage is formed with a first communication port opened to the inside of the high-concentration ink layer and a second communication port opened to the inside of the low-concentration ink layer.
Since the ink cartridge is thus configured, when ink is supplied to the record apparatus head, the ink in the high-concentration ink layer flows through the first communication port into the ink flow passage, the ink in the low-concentration ink layer flows through the second communication port into the ink flow passage, and the ink in the high-concentration ink layer and the ink in the low-concentration ink layer merge in the ink flow passage.
Further, it is desirable that the first communication port is disposed at the lowest position in the gravity direction in the ink storage chamber.
Since the ink cartridge is thus configured, the ink at the lowest position in the gravity direction in the ink storage chamber flows through the first communication port into the ink flow passage.
Further, it is desirable that the flow amount ratio between the flow amount a of ink passing through the first communication port and the flow amount b of ink passing through the second communication port, a:b, is set in the range of 1:1 to 1:3.
Since the ink cartridge is thus configured, it is possible to avoid such a case that the flow-through resistance of the first communication port becomes too large as compared with that of the second communication port (the flow-through resistance ratio becomes insufficient) and the flow amount of ink passing through the first communication port is lessened.
A partition wall having both the communication ports is provided in the upper ink storage chamber.
Since the ink cartridge is thus configured, in the upper ink storage chamber, when ink is supplied to the record apparatus head, the ink in the high-concentration ink layer flows through the first communication port into the ink flow passage, the ink in the low-concentration ink layer flows through the second communication port into the ink flow passage, and the ink in the high-concentration ink layer and the ink in the low-concentration ink layer merge in the ink flow passage.
An ink guide path for causing ink to flow from a storage chamber upper part to a storage chamber lower part in an ink supply state can also be provided in the upper ink storage chamber.
Since the ink cartridge is thus configured, in the upper ink storage chamber, when ink is supplied to the record apparatus head, when ink passes through the ink guide path, it flows from the storage chamber lower part to the storage chamber upper part while it is mixed.
On the other hand, according to the invention, there is provided an ink jet record apparatus comprising a carriage for mounting a head, that can be reciprocated between a print area and a non-print area, using any of the ink cartridges described above.
According to the configuration, when ink is supplied to the record apparatus head, the ink in the high-concentration ink layer in the ink storage chamber and the ink in the low-concentration ink layer flow and merge in the ink flow passage.
Therefore, the ink in the high-concentration ink layer and the ink in the low-concentration ink layer are mixed for supply to the record apparatus head, so that there cab be provided the ink jet record apparatus that can provide uniform print density and quality.
The present disclosure relates to the subject matter contained in Japanese patent application Nos. 2001-148296 (filed on May 17, 2001), and 2001-205163 (filed on Jul. 5, 2001), which are expressly incorporated herein by reference in their entireties.